High CPU causing laptop to be slow(task manager)


New Member

My dad gave me his laptop just to check an issue. His Laptop when first given to me check was constantly running high CPU when checking task manager with it running 100% and I couldn't identify what was making it do this. So a quick restart (off and back on) the laptop was doing the same so it was not a an app nor a programme causing this. I did a some googling and read it could be a Virus or malware so I downloaded and installed Avast premium and scanned and there was zero viruses on the laptop. I then proceeded with Ccleaner Professional and updated all his drivers and also did a full clean on it whilst also fixing any errors which could potentially be making the laptop run slow but still no luck.

When on task manager the 100% cpu usuage has gone but theres still something running in the background making it run slow and CPU increase and decrease constantly when no programs are running. A simple forum page on google chrome or watching a youtube video has become a huge painful task because the laptop is running so slow.

Can anybody help try and fix the issue or know what the problem could be? If push comes to shove I have mentioned doing a full reboot from factory but I would like to try and fix the issue just in case it happens again for future reference.

The laptop is a Lenovo thinkpad/ideapad 330



Active Member
Hello Wilkesy91, Hope you are safe and good.
Seeing to your issue, first of all check in the task manager which service/task is taking up space or is running in background. They can be apps, software's, Microsoft Services, Windows Defender running/scanning and its service Antimalware service Executable.
If that is running, then thats means that either Defender is running a background scan or their is virus/malware tampering with your device. In that case I would suggest you to firstly uninstall all the antivirus even the Avast Premium and install Malwarebyte and Run a full system scan.

Along with that, you can also check Windows Update manually as sometimes the ML doesn't pushes you update on time. If other task running in task manager like browser, or some app/software, right click on it and select end process.

Also I would suggest you to not make your pc heavy in terms of downloading third party Updation tools as they just make your pc work more, talking about updates of drivers, if they are needed in your system, then you will get them through the Windows Updates, else you are doing fine.

Now if still it dosent helps out, then try to follow the below more troubleshooting steps and let me know further:

  1. Open Settings.
  2. Click on Privacy.
  3. Click on Background apps.
  4. Under the "Choose which apps can run in the background" section, turn off the toggle switch for the apps you want to restrict.


1. Press CTRL + SHIFT + Esc keys together from your keyboard.

2. Go to startup tab.

3. Right click and Disable all Programs, except the Microsoft one's.


Press Windows key + R
Type: msconfig
Hit Enter

Go to the services tab
Check the box, hide all Microsoft services

Disable the remaining services

Click Apply then OK, Restart if prompted

These all should do it. Kudos :)


Cloud Security Engineer
Staff member
There are many reasons for a spiking CPU and the CPU generally will never be 0% even while idling due to all the processes typically running, background tasks and services running, checking for updates etc.

Things that can cause CPU spikes
  • Updates (whether they're Windows or software these typically run more often when a system is idle)
  • Operating system corruption ( corruption can cause system components to become unstable and I've seen spikes due to this : run SFC /SCANNOW from a command prompt to attempt to detect and repair corrupted components)
  • Malware : there are many types of malware particularly crypto miners that will run during system idle
  • Cheap hardware : This is pretty common where someone just buys a cheap laptop and the CPU is just overwhelmed by the OS and applications. The only way to fix this is get a better system
  • Endpoint protection software : Quite a few security vendors software are very resource heavy and can impact performance
  • High memory utilization if memory usage is above 70% you can encounter CPU thrashing (this is where the CPU is spending a lot of time swapping data in and out of memory since physical RAM is getting full. You can add more RAM if this is the case.

You can also try running a program like Procexp Process Explorer - Windows Sysinternals which can provide better live statistics on performance than the build in task manager


New Member
cheers for the replys guys. I dont currently have the laptop but I will be popping back to my dads on tuesday and will certainly be having another go.

The one the rings a bell, I did notice service Antimalware service Executable been on top of the CPU chart all the time spiking from 60%-100% never under, it was like it was running but never stopping either. So could it potentially be some sort of malware messing around in the background?